Abstract:

In order to improve the electrocatalytic performance of carbon supported Pd(Pd/C) anodic catalyst for formic acid oxidation in the direct formic acid fuel cell(DFAFC), the effect of ethylenediamine-tetramethylene phosphonic acid(EDTMP) added into the electrolyte on the electrocatalytic performance of Pd/C catalyst for formic acid oxidation was investigated using the energy dispersive X-ray spectroscopy(EDS), X-ray diffraction(XRD) pattern, transmission electron microscopy(TEM) and electrochemical techniques. The Pd/C catalyst electrode in the electrolyte with 0.5 mmol/L EDTMP displays the best electrocatalytic activity and stability for formic acid oxidation. This result is attributed to that the adsorbed EDTMP on the surface of Pd not only decreases the amount of adsorbed CO at the Pd/C catalyst electrode by the ensemble effect but also inhibits the decomposition of formic acid over the Pd/C catalyst to decrease the CO poisoning. However, when the concentration of EDTMP is higher than 0.5 mmol/L, overfull adsorbed EDTMP would occupy the active sites of Pd to decrease the electrocatalytic performance.

Key words: Carbon supported Pd catalyst, Formic acid oxidation, Ethylenediamine-tetramethylene phosphonic acid, Decomposition of formic acid